Method for preparing a urea-extended phenolic resole resin stabilized with an alkanolamine

Abstract

A water-soluble urea-extended phenol-formaldehyde resole resin stabilized with an alkanolamine alone or combined with a monosaccharide or disaccharide, methods of manufacturing the resin and using it, and products prepared using the resin.

I claim: 
     
       1. In a method for preparing a urea-extended phenolic resole resin, comprising preparing a phenolic resole resin by reacting formaldehyde (F) and phenol (P) at an F:P mole ratio in the range of about 2:1 to 6:1 under aqueous alkaline reaction conditions and reacting free formaldehyde in the phenolic resole resin with urea to form a urea-extended phenolic resole resin, the improvement comprising adding an alkanolamine to the phenolic resole resin, in an amount sufficient to improve the storage stability of the urea-extended phenolic resole resin, either prior to or contemporaneously with the urea reaction with the phenolic resole resin. 
     
     
       2. The method of claim 1, further comprising cooling the resin to between about 10° and 50° C. and adjusting the resole resin to a pH between about 6.5 and 11 prior to adding the alkanolamine, adding the alkanolamine, and then heating the resin to between about 15° C. and 50° C. 
     
     
       3. The method of claim 1 wherein the urea is added contemporaneously with the alkanolamine. 
     
     
       4. The method of claim 1 wherein the urea is added after the addition of the alkanolamine. 
     
     
       5. The method of claim 1 wherein the alkanolamine is selected from the group consisting of triethanolamine, diethanolamine, tripropanolamine, and dipropanolamine. 
     
     
       6. The method of claim 5 wherein the alkanolamine is diethanolamine. 
     
     
       7. The method of claim 2 wherein the pH is adjusted to between about 7.5 and 9. 
     
     
       8. The method of claim 1 wherein a monosaccharide or disaccharide is added along with the alkanolamine in an amount effective to improve storage stability of the urea-extended phenolic resole resin. 
     
     
       9. The method of claim 8, further comprising cooling the resin to between about 10° and 50° C. and adjusting the resole resin to a pH between about 6.5 and 11 prior to adding the alkanolamine and the monosaccharide or disaccharide, adding the alkanolamine and the mono- or disaccharide, and then heating the stabilized resin to between about 15° C. and 50° C. 
     
     
       10. The method of claim 8 wherein the urea is added contemporaneously with the alkanolamine and the monosaccharide or disaccharide. 
     
     
       11. The method of claim 8 wherein the urea is added after the addition of the allanolamine and the monosaccharide or disaccharide. 
     
     
       12. The method of claim 8 wherein the monosaccharide or disaccharide is selected from the group consisting of sorbitol, sucrose, and fructose. 
     
     
       13. The method of claim 12 wherein the monosaccharide is sorbitol. 
     
     
       14. The method of claim 8 wherein the alkanolamine is selected from the group consisting of triethanolamine, diethanolamine, tripropanolamine, and dipropanolamine. 
     
     
       15. The method of claim 14 wherein the alkanolamine is diethanolamine. 
     
     
       16. The method of claim 9 wherein the pH is adjusted to between about 7.5 and 9. 
     
     
       17. The method of claim 8 wherein the alkanolamine and the monosaccharide or disaccharide are each added in amounts between 0.25 to 20 wt % based on the phenolic resole resin prior to addition of urea, and the ratio of the alkanolamine to the monosaccharide or disaccharide is between about 1:2 and 2:1. 
     
     
       18. A storage stable urea-extended phenlic resole resin prepared by adding an alkanolamine to the phenolic resole resin either prior to or contemporaneously with urea addition to the phenolic resole resin, wherein the alkanolamine is added in an amount sufficient to improve the storage stability of the urea-extended phenolic resole resin. 
     
     
       19. A storage stable urea-extended phenolic resole resin prepared by adding 1) an alkanolamine and 2) a monosaccharide disaccharide to a phenolic resole resin either prior to or contemporaneously with urea addition to the phenolic resole resin, wherein the alkanolamine and the monosaccharide or disaccharide are added in an amount sufficient to improve the storage stability of the urea-extended phenolic resole resin.